David didn't mind tilting at windmills.  He received his PhD in chemical engineering from the University of Illinois in 1961 and went to work at Lawrence-Livermore National Laboratory.  He was involved in many projects, such as underground coal gasification, but it was in 1984 when he was asked to do a study on the stability of our nuclear deterrent program with the Soviet Union, that he received the most attention.  The doctrine behind the nuclear deterrent program was called Mutual Assured Destruction, otherwise known as MAD.

The idea of MAD was that if both the Russians and the United States had enough nuclear bombs to destroy each other a few times over, neither side would ever take that step.  It was called the "balance of terror."  David began his project thinking he would discover that this policy made sense for both sides.

Unfortunately, he found that the Russians were tunneling out enormous underground facilities around all their major cities and he started to consider the unthinkable.  Did the Russians believe they could win a nuclear war?

And so David, being David, wrote a book called Beyond Star Wars in which he urged the United States to begin a crash program of building their own massive shelters.

Needless to say, he didn't win himself many friends.  One of his colleagues, Dr. Walter Alvarez, best-known for his theory that the dinosaurs were wiped out by a giant meteor, accused him of wanting to cause another mass extinction event.

But David was just calling it as he saw it.  And in his mind he was trying to save the world.

It's not surprising that when David retired from the lab in 1997 he took on a new challenge, human health.  He founded a company called Krysalis, after the structure a caterpillar creates in order for a transformation to take place and it becomes a butterfly.  And he became interested in autism.

I recall driving over to his home in Moraga, the front overgrown with bushes, the interior filled with medical books, and his large backyard with a view of rolling hills and was always filled turkeys and racoons.  David was one of those people who lived in the mind, but he was also a person who loved the natural world.  He'd never win any Good Housekeeping awards, but I always felt a sense of tranquility at his home.  It was the tranquility of the forest, of the quiet glen, of the man who looks up to the heavens and ask his questions with a childlike innocence.

Because you see, I don't think God minds our questions, even when they penetrate to the very center of the universe.  I think He delights in showing us His handiwork.  He loves it when we solve His riddles.  Only those with true curiousity will ever share with God the true delight of His creation.  I believe that's why those who spend their lives asking the big questions always seem so much younger than their chronological age.  When I see pictures of Einstein I always think he looks like he's having a blast.  David had that look.  He was never happier than when he was trying to solve a problem nobody else had figured out.

During the time I worked with David I always thought of him as my own personal Doc Brown, the character played by Christopher Lloyd in the Back to the Future series of movies.  And just like Doc Brown, sometimes with David there were those things which didn't quite fit.

Even though it was many years after the Soviet Union had fallen apart when we met I asked him about his theories.  Despite his warnings the United States never did build large, underground shelters.  And yet we survived.  Even so many years after the fact he still seemed surprised.  Was he wrong?  Were we lucky?  He seemed to have no clear idea, and I always wondered if some small part of him wasn't still expecting an attack.

And now you have left us, David.  You can ask all your questions directly of God.   And I know He will delight in showing you His handiwork.  And as as scientist I know you'll stand back and say, "Wow, I would never have thought of that!"  Only a real fan can appreciate the work of a master.

I know when you meet God you'll thank Him for sparing our world from nuclear war.  I know you'll thank him for your family and friends.  But you still had unanswered questions and autism was one of them.  I want you let let Him know that the time is right for an answer to the questions of autism, especially for my daughter, who you tried so hard to help.

Someday we will meet again, and when I finally shuffle off this mortal coil, I hope  autism will be as distant a worry as nuclear war is for us today.  And when I pass through that veil I hope my aged face will  have the same blissful, curious, having a blast look yours always did.

Good-bye my friend.

Kent Heckenlively is a Contributing Editor to Age of Autism